Acidic fractional ester of a polycarboxylic acid with oxypropylated glucose



Patented Jan. 27, 1953 ACIDIC FRACTIONAL ESTER OF A POLYCAR- BOXYLIC ACID WITH OXYPROPYLATED GLUCOSE Melvin De Groote, University City, Mo., assignor to Petrolite Corporation, a corporation of Delaware No Drawing. Application May 14, 1951, Serial No. 226,327

The present invention is a continuation-inpart of my co-pending applications, Serial Nos. 104,801 and 104,802, both filed July 14, 1949, and of which the former application is now Patent 2,552,528 issued May 15, 1951 and the latter application is now abandoned.

The present invention is concerned with certain new chemical products, compounds, or compositions which have useful application in various arts. It includes methods or procedures for manufacturing said new chemical products, compounds or compositions, as well as the products, compounds, or compositions themselves.

Complementary to the above aspect of the invention herein disclosed is my companion invention concerned with the use of these particular chemical compounds, or products, as demulsiiying agents in processes or procedures particularly adapted for preventing, breaking, or resolving emulsions of the water-in-oil type, and particularly petroleum emulsions. See my co-pending application, Serial No. 226,326, filed May 14, 1951.

Said aforementioned co-pending application, i. e., Serial No. 104,801, may be characterized by claim one of said application, which is as follows:

A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including high molal oxypropylation derivative of monomeric polyhydric compounds with the proviso that (a) the initial polyhydric reactant be free from any radical having at least 8 uninterrupted carbon atoms; (2)) the initial polyhydric reactant have a molecular weight not over 1200 and at least 4 hydroxyl radicals; (c) the initial polyhydric reactant be water-soluble and xyleneinsoluble; (d) the oxypropylation end product be water-insoluble and xylene-soluble; (e) the oxypropylation end product be within the molecular weight range of 2000 to 30,000 on an average statistical basis; the solubility characteristics of the oxypropylation end product in respect to water and xylene be substantially the result of the oxypropylation step; (9) the ratio of propylene oxide per hydroxyl in the initial poly- 8 Claims. (Cl. 2609) hydric reactant be within the range of 7 to '70; (h) the initial polyhydric reactant represent not more than l2 /z% by weight of the oxypropylation end product on a statistical basis, and (i) the preceding provisos being based on complete reaction involving the propylene oxide and the initial polyhydric reactant.

Claim 1 of Serial No. 104,802, filed July 14, 1949, is substantially the same, except that it is concerned with the high molal oxypropylation derivatives as such and not specifically for demulsification.

In said co-pending applications, Serial Nos. 104,801, and 104,802, I have pointed out that the hydroxylated compounds therein described could be converted into new derivatives which have the properties of the original hydroxylated compounds insofar that they are effective and valuable demulsifying agents for the resolution of water-in-oil emulsions as found in the petroleum industry.

Among such derivatives are a variety of esters of polycarboxy acids and particularly acidic fractional esters derived from polycarboxy acids. A number of suitable polycarboxy acids were enumerated in said co-pending applications, Serial Nos. 104,801, and 104,802.

The present invention is concerned with these last-mentioned previously-described acidic esters as new chemical compounds. These particular esters are derived from oxypropylated glucose, frequently referred to as dextrose and sometimes known as grape sugar. As is well known, it is an aldohexose.

More specifically then, the present invention is concerned with acidic fractional esters; said acidic fractional esters being obtained by reaction between (A) a polycarboxy acid, and (B) high molal oxypropylation derivatives of glucose, with the proviso that (a) the oxypropylation end-product be within the molecular weight range of 1,500 to 15,000 on an average statistical basis; (b) the oxypropylation end-product be xylene-soluble; (c) the xylene-soluble characteristics of the oxypropylation end-product be substantially the result of the oxypropylation step; (d) the initial polyhydric reactant represent not more than 12% by weight of the oxypropylation end-product on a statistical basis, and that (e) the preceding provisos be based on complete reaction involving the propylene oxide and the initial polyhydric reactant, with the proviso that the ratio of (A) to (B) be one mole of the polycarboxy acid for each available hydroxyl radical.

Although the herein described products have a number of industrial applications, they are of particular value for resolving petroleum emulsions of the water-in-oil type that are commonly referred to as cut oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion. This specific application is described and claimed in my co-pending application, Serial No. 226,326, filed May 14,1951.

The new products are useful as wetting, detergent and leveling agents in the laundry, textile and dyeing industries; as wetting agents and detergents in the acid washing of building stone and brick; as wetting agents and spreaders in the application of asphalt in road building and the like; as a flotation reagent in the flotation separation of various aqueous suspensions containing negatively charged particles, such as sewage, coal washing waste water, and various trade wastes and the like; as germicides, insecticides, emulsifying agents, as, for example, for cosmetics, sp ay oils. waterepellent te ti e. finishes. as

bricants, etc.

PART 1 For a number of well known reasons equipment, whether laboratory size, semi-pilot plant size, pilot plant size, or large scale size, is not as a rule designed for a particular alkylene oxide. Invariably and inevitably, however, or particularly in the'case of laboratory equipment and pilot plant size the design is such as to use any of the customarily available alkylene oxides, i. e., ethylene oxide, propylene oxide, butylene oxide, glycide, epichlorohydrin, styrene oxide, etc. In the subsequent description of the equipment it becomes obvious that it is adapted for oxyethylation as well as oxypropylation.

Oxypropylations are conducted under a wide variety of conditions, not only in regard to presence or absence of catalyst,and the kind of catalyst. but also in regard to the time of reaction, temperature of reaction, speed of reaction, pressure during reaction, etc. For instance, oxyalkylations can be conducted at temperatures up to approximately 200 C. with pressures in about the same range up to about 200 pounds per square inch. They can be conducted also attemperatures approximating the boiling point of water or slightly above, as for example 95 to 120 C. Under such circumstances the pressure will be less than pounds per square inch unless some special procedure is employed as is sometimes the case, to wit, keeping an atmosphere of inert gas such as nitrogen in the vessel during the reaction. Such low-temperature-low reaction rate .cident.

oxypropylations have been described very completely in U. S. Patent No. 2,448,664, to H. R. Fife, et al., dated September 7, 1948. Low temperature, low pressure oxypropylations are particularly desirable where the compound being subjected to oxypropylation contains one, two or three points of reaction only, such as monohydric alcohols, glycols and triols.

Although the word glycol or diol is usually applied to compounds containing carbon, hydrogen, and oxygen only, yet the nitrogen-containing compounds herein are diols in the sense that they are dihydroxylated. Thus, the conditions which apply to the oxypropylation of certain glycols also apply in this instance.

Since low pressure-low temperature reaction speed oxypropylations require considerable time, for instance, 1 to '7 days of 24.- hours each to comwhether on a laboratory scale, pilot plant scale,

or large scale, so as to operate automatically.

The prior figure of seven days applies especially to large-scale operations. I have used conventional equipment with two added automatic features; (a) a solenoid controlled valve which shuts off the propylene oxide in event that the temperature gets outside a predetermined and set range, for instance, to C., and (12) another solenoid valve which shuts off the propylene oxide (or for that matter ethylene oxide if it is being used) if the pressure gets beyond a predetermined range, such as 25 to 35 pounds. Otherwise, the equipment is substantially the same as is com.- monly mpl y d to this. p rpose wher the p es sure or reaction is higher, speed of reaction is higher, and time of reaction is much shorter. In such instances such automatic controls are not necessarily used.

Thus, in preparing the various examples I have found it particularly advantageous to use laboratory equipment or pilot plant which is designed to permit continuous oxyalkylation whether it be oxypropylation or oxyethylation. With certain obvious changes the equipment can be used also to permit oxyalkylation involving the use of glycide where no pressure is involved except the vapor pressure of a solvent, if any, which may have been used as a diluent.

As previously pointed out the method of using propylene oxide is the same as ethylene oxide. This point is emphasized only for the reason that the apparatus is so designed and constructed as to use either oxide.

The oxypropylation procedure employed in the preparation of the oxyalkylated derivatives has been uniformly the same, particularly in light of the fact that a continuous automatically-controlled procedure Was employed. In this procedure the autoclave was a conventional autoclave made of stainless steel and having a capacity of approximately 15 gallons and a working pressure of one thousand pounds gauge pressure. This pressure obviously is far beyond any requirement as far as propylene oxide goes unless there is a reaction of explosive violence involved due to ac- The autoclave was equipped with the conventional devices and openings, such as the variable-speed stirrer operating at speeds from 50 R. P. M. to 500 R. P. M.; thermometer well and thermocouple for mechanical thermometer; emptying outlet, pressure gauge, manual vent line; charge hole for initial reactant; at least one connection for introducing the alkylene oxide,

.such as propylene oxide or ethylene oxide, to the bottom of the autoclave; along with suitable devices for both cooling and heating the autoclave, such as a cooling jacket, and, preferably, coils in addition thereto, with the jacket so arranged that it is suitable for heating with steam or cooling with water and further equipped with electrical heating devices. Such autoclaves are, of course, in essence small-scale replicas of the usual conventional autoclave used in oxyalkylation procedures. In some instances in exploratory preparations an autoclave having a smaller capacity, for instance, approximately 3% liters in one case and about 1% gallons in another case, was used.

Continuous operation, or substantially continuous operation, was achieved by the use of a separate container to hold the alkylene oxide being employed, particularly propylene oxide. In conjunction with the smaller autoclaves, the container consists essentially of a laboratory bomb having a capacity of about one-half gallon, or somewhat in excess thereof. In some instances a larger bomb was used, to wit, one having a capacity of about one gallon. This bomb was equipped, also, with an inlet for charging, and an eductor tube going to the bottom of the container so as to permit discharging of alkylene oxide in the liquid phase to the autoclave. A bomb having a capacity of about 60 pounds was used in connection with the -gallon autoclave. Other conventional equipment consists, of course, of the rupture disc, pressure gauge, sight feed glass, thermometer connection for nitrogen for pressuring bomb, etc. The bomb was placed on a scale during use. The connections between the bomb and the autoclave were flexible stainless steel hose or tubing so that continuous weighings could be made without breaking or making any connections. This applies also to the nitrogen line, which was used to pressure the bomb reservoir. To the extent that it was required, any other usual conventional procedure or addition which provided greater safety was used, of course, such as safety glass protective screens, etc.

Attention is directed again to what has been said previously in regard to automatic controls which shut ofi the propylene oxide in event temperature of reaction passes out of the predetermined range or if pressure in the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations become uniform in that the reaction temperature was held within a few degrees of any selected point, for instance, if 105 C. was selected as the operating temperature the maximum point would be at the most 110 C. or 112 C., and the lower point would be 95 or possibly 98 C. Similarly, the pressure was held at approximately 30 pounds maximum within a 5-pound variation one way or the other, but might drop to practically zero, especially where no solvent such as xylene is employed. The speed of reaction was comparatively slow under such conditions as compared with oxyalkylations at 200 0.

Numerous reactions were conducted in which the time varied as far as a partial oxypropylation step was concerned from 8 to 12 hours, and in some instances even from 14 to 18 hours. In some instances the reaction may have taken place in considerably less time, for instance, onehalf or two-thirds the indicated time. In the series subsequently used for illustration the minimum time recorded was 8 hours. Reactions indicated as being complete in 8 hours may have been complete in a lesser period of time in light of the automatic equipment/employed. This applies also where the reactions were complete in a longer period of time, for instance, 10 or 12 hours.

In the addition of propylene oxide, in the autoclave equipment as far as possible the valves were set so all the propylene oxide if fed continuously would be added at a rate so that the predetermined amount would react within the first 15 hours of the 24-hour period or two-thirds of any shorter period. This meant that if the reaction was interrupted automatically for a period of time for pressure to drop or temperature to drop the predetermined amount of oxide would still be added in most instances well within the predetermined time period. Sometimes where the addition was a comparatively small amount in a 10-hour period there would be an unquestionable speeding up of the reaction, by simply repeating the examples and using 3, 4 or 5 hours instead of 10 hours.

When operating at a comparatively high temperature, for instance, between 150 to 200 C., an unreacted alkylene oxide such as propylene oxide, makes its presence felt in the increase in pressure or the consistency of a higher pressure. However, at a low enough temperature it may happen that the propylene oxide goes in as a liquid. If so, and if it remains unreacted there is, of course, an inherent danger and appropriate steps must be taken to safeguard against this possibility; if need be a sample must be withdrawn and examined for unreacted propylene oxide. One obvious procedure, of course, is to oxypropylate at a modestly higher temperature, for instance, at 140 to 150 C. Unreacted oxide affects determination of the acetyl or hydroxyl value of the hydroxylated compound obtained.

The higher the molecular weight of the compound, i. e., towards the latter stages of reaction, the longer the time required to add a given amount of oxide. One possible explanation is that the molecule, being larger, the opportunity for random reaction is decreased. Inversely, the lower the molecular weight the faster the reaction takes place. For this reason, sometimes at least, increasing the concentration of the catalyst doe not appreciably speed up the reaction, particularly when the product subjected to oxyalkylation has a comparatively high molecular weight. However, as has been pointed out previously, operating at a low pressure and a low temperature even in large scale operations as much as a week or ten days time may lapse to obtain some of the higher molecular weight derivatives from monohydric or dihydric materials.

In a number of operations the counterbalance scale or dial scale holding the propylene oxide bomb was so set that when the predetermined amount of propylene oxide had passed into the reaction the scale movement through a time operating device was set for either one to two hours so that reaction continued for 1 to 3 hours after the final addition of the last propylene oxide and thereafter the operation was shut down. This particular device is particularly suitable for use on larger equipment than laboratory size autoclaves, to wit, on semi-pilot plant or pilot plant size, as well as on large scale size. This final stirring period is intended to avoid the presence of unreacted oxide.

In this sort of operation, of course, the temperature range was controlled automatically by either use of cooling water, steam, or electrical reaction vessel was also automatic insofar that the feed stream was set for a slow continuous E a pl a 50.13 pounds of the reaction mass equivalent to 3.46 pounds of dextrose, 37.57 pounds of prorun which was shut off in case the pressure pyl ne oxide, .43 pound of sodium methy and passed a predetermined point as previously set p u d of S n identified s out. All the points of design, construction, etc., ampl 1o, pr in w re subjected o f rther were conventional including the gases, check xypr pyl i n u der Substantially the m valves and entire equi ment. As far as I am conditions as described in Ex mp 1 p r i awarc at least two firms, and possibly three, larly in regard to tempe and P N0 specialize in autoclave equipment such as I have d l. at y s o ucedemployed in the laboratory and are prepared to The reaction time was 3 /4 hOllI'S. The amount furnish equipment of this same kind. Similarly f x e added w s 18.75 pounds e p pyl n pilot plant equipment is available. This point is Oxide s introduced the rate Of ab /2 simply made as a precaution in the direction of pounds per h At vthe Completion of the esafety. Oxyalkylations, particularly involving c P rt Of t ass Was Withdrawn as a ethylene oxide, gl cide, propylene id 1 sample and the remainder subjected to further should not be conducted except in equipment p py as described in Example specifically designed for the purpose. mediately l g- Emample Example 3a The starting material was commercial anhydrous glucose commonly sold under the name of Pounds of the reaction ss p v us y anhydrous dextrose. The catalyst employed was identlfied as Example 211 d q v e to sodium methylate. The solvent employed was Po of dextrose, -8 pounds of opy e the diethyl ether of diethylene glycol. The autooxide, 33 pound of s dlu ethylate, and 6.75 cla d was one having capacity of about pounds of solvent, were subjected to further oxy- 15 gallons or approximately 1 5 pounds The propylationv in the same manner as described in equipment had all the control devices previously the two Preceding a pl No added catalyst describ d T speed of t stirrer could be was employed. Conditions as far as temperature varied from 150 t 350 R. P, 4 pounds of and pressure were concerned were the same as in hydrous glucose were charged into the autoclave. mples. 111 and. 2a, preceding. The tim re- To this was added pound of sodium methylate quired add the OXide W s 1 hours- The and 10 pounds of the diethylether of diethylene o t of oxide added w s 30.74 p unds, which glycol. The reaction pot was flushed out with wasadded at the rate of about 3 pounds per hour. nitro en, Th autodave was soaked and the At the. completion of the reaction part of the automatic devices adjusted for injecting 43.25 p e Was Wi hdrawn. and the remainder subpounds of propylene oxide in about 8 hours. The jected t0 furtherv O Y'D PY iOI as noted in EX- injection was at the rate of about 6 pounds per ample 4a,immediate1y ol hour. This time period was comparatively short 40 due in part to the fact that there was present E$ample a considerable concentration of catalyst. This particular oxypropylation was conducted at a 64 pounds of the react1n mas s ldentlfied as temperature moderately above the boiling point Example 3a, precedmg and equivalent to f water, abo t; 250 to 2 00 R The pressure pounds of dextrose, 56.58 pounds of propylene regulat was et for a maximum f 5 pounds oxide, .25 pound of sodium methylate, and 5.13 before actually proceeding with this particular Pounds f Solvent, Wele Subjected o further O Y- oxypropylation step, and in all the succeeding p py n n the same manner as described in steps as exemplified by Examples 2a, 3a and 4a. the three previous examples. Conditions as far the pressure did not go above 20 pounds per as temperature and pressure were concerned were square inch. This was due probably to the fact the same as in the previous examples. No added that propylene oxide reacted rather rapidly at catalyst was introduced The time required to thls particular temperature m 1 b? the add the oxide was 10 hours. The amount of oxide g g catalirst pre.sent' The mmal mtrof added was 13.12 pounds. The oxide was added uc ion o piopy ene oxide was not started until at the rate of about 11/2 pounds per hour The the heating devices had raised the temperature f 1 d I b b1 t th to above the boiling point of water, for instance, a 1 Ion 0 0X1 6 was s OW ue pro a y 0 9 approximately 2400 to R All tom, the increased size of molecule and also to the lower action was complete in less than 8 hours but concentration i f stirring was continued to the end of the 8-hour What been 5am regard to iheprecedms e i d, t th end of this reaction time, part examples is presented in tabular form in Table 1, of the reaction mass was withdrawn as a sample following with 501118 added information as to and the remainder subjected to further oxyl c r weight and s to l i y f e r .propylation as described in Example 2a, following, action product in water, xylene, and kerosene.

TABLE 1 Composition Before Composition at End Max v v Max. Pres, -m y 11.0 Oxide Cata- Sol- Theo -H.C Oxide 'Catae Sol- Hyd T211513?" his? Amt, Amt., lyst, vent, M 7' Amt, Amt, lyst, vent, M01. in

lbs. lbs lbs. lbs. lbs. lbs. lbs. lbs. Wt.

acetyl or hydroxyl value.

- Example 1a was soluble in both water and xylene but insoluble in kerosene; Example 2a was emulsifiable in water, soluble in xylene, and dispersible in kerosene; Examples 3a and 4a were insoluble in water, and soluble in both xylene and kerosene.

In other comparable oxypropylations I have employed increased amounts of propylene oxide in ratios to the point where approximately twice the amount of propylene oxide was used as in the above examples, 1. e., where the glucose represented 1% or less of the final product. However, under such circumstances there was not the proportional increase in the hydroxyl molecular weight which rose, for example, to a maximum of 5,000 or 5,500, based on a theoretical molecular weight of about 12,000 or slightly higher. In all such instances the products were insoluble in water and soluble in both xylene and kerosene.

The final products were quite dark in color and were somewhat viscous liquids. This was more or less characteristic of all the oxypropylated products at the various stages. The color of all these products was reddish. In some cases it was so dark as to be nearly black. These products were, of course, slightly alkaline due to the residual sodium methylate. The residual basicity due to the catalyst, of course, would be the same as if caustic soda had been used.

Speaking of insolubility in water or solubility in kerosene such solubility test can be made simply by shaking small amounts of the materials in a test tube with water, for instance, using 1% to 5% approximately based on the amount of water present.

Needless to say, there is no complete conversion of propylene oxide into the desired hydroxylated compounds. This is indicated by the fact that the theoretical molecular weight based on a statistical average is greater than the molecular weight calculated by usual methods on basis of Actually, ther is no completely satisfactory method for determining molecular weights of these types of compounds with a high degree of accuracy when the molecular weights exceed 2,000. In some instances the acetyl value or hydroxyl value serves as satisfactorily as an index to the molecular weight as any other procedure, subject to the above limitations, and especially in the higher molecular Weight range. If any difficulty is encountered in the manufacture of the esters as described in Part 2 the stoichiometrical amount of acid or acid compound should be taken which corresponds to the indicated acetyl or hydroxyl value. This matter has been discussed in the literature and is a matter of common knowledge and requires no further elaboration. In fact, it is illustrated by some of the examples appearing in the patent previously mentioned.

PART 2 acid or anhydride, citraconic' acid or anhydride,

maleic acid or anhydride adducts as obtained by the Diels-Alder reaction from products such as maleic anhydride, and cyclopentadiene. Such acids should be heat stable so they are not decomposed during esterification. They may contain as many as 36 carbon atoms as, for example, the acids obtained by dimerization of unsaturated fatty acids, unsaturated monocarboxy fatty acids, or unsaturated monocarboxy acids having 18 carbon atoms. Reference to the acid in the hereto appended claims obviously includes the anhydrides or any other obvious equivalents. My preference, however, is to use polycarboxy acids having not over 8 carbon atoms.

The production of ester including acid esters (fractional esters) from polycarboxy acids and glycols or other hydroxylated compounds is well known. Needless to say, various compounds may be used such as the low molal ester, the anhydride, the acyl chloride, etc. However, for purpose of economy it is customary to use either the acid or the anhydride. A conventional procedure is employed. On a laboratory scale one can employ a. resin pot of "the kind described in U. S. Patent No. 2,499,370, dated March '7, 1950 to De Groote and Keiser, and particularly with one more opening to permit the use of a porous spreader if hydrochloric acid gas is to be used as a catalyst. Such device or absorption spreader consists of minute Alundum thimbles which are connected to a glass tube. One can add a sulfonic acid such as paratoluene sulfonic acid as a catalyst. There is some objection to this because in some instances there is some evidence that this acid catalyst tends to decompose or rearrange heat-oxypropylated compounds, and particularly likely to do so if the esterification temperature is too high. In the case of polycarboxy acids such as diglycollic acid, which is strongly acidic there is no need to add any catalyst. The use of hydrochloric acid gas has one advantage over paratoluene sulfonic acid and that is that at the end of the reaction it can be removed by flushing out with nitrogen, whereas there is no reasonably convenient means available of removing the paratoluene sulfonic acid or other sulfonic acid employed. If hydrochloric acid is employed one need only pass the gas through at an exceedingly slow rate so as to keep the reaction mass acidic. Only a trace of acid need be present. I have employed hydrochloric acid gas or the aqueous acid itself to eliminate the intial basic material. My preference, however, is to use no catalyst whatsoever.

The products obtained in Part 1 preceding may contain a basic catalyst. As a general procedure I have added an amount of half-concentrated hydrochloric acid considerably in excess of what is required to neutralize the residual catalyst. The mixture is shaken thoroughly and allowed to stand overnight. It is then filtered and refluxed with the xylene present until the water can be separated in a phase-separating trap. As soon as the product is substantially fre from water the distillation stops. This preliminary step can be carried out in the flask to be used for esterification. If there is any further deposition of sodium chloride during the reflux stage needless to say a second filtration may be required. In any event the neutral or slightly acidic solution of the oxypropylated derivatives described in Part 1 is then diluted further with sufiicient xylene, decalin, petroleum solvent, or the like, so that one has obtained approximately a 40% solution. To this actant as previously described, such as phthalic anhydride, succinic acid or anhydride, diglycollie acid, etc. The mixture i's refluxed untiiestenm f2 peculiarities of structure insofar that one or the original reactants, for instance,dipentaerythritxfl or 'tripentaerythritol, are much less soluble in water than one might ordinarily expect on the cation is complete as indic'ated by elimination of 5 carbon-oxygen ratio. After the water is removed water-or drop in carboxyl value. Needless to say, in the case of the esterification by means of a if one produces a half-ester from an anhydride water-insoluble solvent, such as benzene, xylene such as phthalic anhydride, no water is elimior the use of some other comparable solvent or nated. However, if it is obtained from diglycollic mixtures, one is confronted with the fact that the acid, for example, water iseliminat'e'd. -All' such acidic ester is not necessarily soluble in such no'nprocedures were conventional and have been so polar solvent, and possibly because it-eitherdoes thoroughly described-in the literaturethat further cross-link or at least gives a pseudo gel. I have consideration will be lim'ited'to a few examples used the terminology pseudo gel for the reason and'a comprehensive table. that such gel is reversible as distinguished from Other procedures for eliminating the residual a true non-reversible gel produced by cross-linkbasic catalyst, if any, can be employed. For *exing. The exact nature of thistendency'to becbm'e ample, the oxyalkylationcan be con'ducted'in ab insoluble or tendency toward gelation is obscure sence of a solvent #or the solvent removed after and not fully understood. In light of the efiect oxypropylation. suchoxypropy lation endeprodof semi-polar solvents there may be some relanot can then be acidifie'd with just enough concen- 2'0 tionship, and in fact an important-one to hydrotrated hydrochloric acid to just neutralize the gen banding factors, residual basic catalyst. To this product one can However, by the addition of a semi-polar s'o'lthen add a small amount of anhydrous sodium vent, such as diethyl carbitol, which is the trade Sulfate (sufficient'inequeifitity'to take p 'anvwater name for diethyle'neglycol diethylether, or some that s p e d e u ject t e s to other similar solventsuch as an alcohoL one tends centrifugal force 50 tis' o "e ate the hydrated to reduce or eliminate this efiect. The alcohol, sodium sulfate and probably the-sodiumchloride of course, must be added at the end of the reacformed. The clear somewhat viscous 'straw-coltionso as to not interfere with the e'sterification. cred amber liquid 80 Obtained may C nta a Small The non-hydroxy semi-polar solvent can be reamount of sodium sulfate or sodium chloride but. tained at the start of esterification provided it n an e tis p rf a p le f r s does not interfere with water removal. In any ca e 1 t manner C I event, one can obtain a homogeneous system in It 1 s to be pomted out that the products here which substantially the entire material is solid. descrlbed are f polyesters the Sense that Referring to the original oxypropyla'tion it will these isda pillllaltllty of both glucose radicals 2 be noted that the diethyl ether of diethylene :E Z E ZS' f g ggggg g c aracterized y glycol was used as a solvent .to give a slurry. By following slight modifications or what as fi gz i g fi fglf ii been said previously one can conduct the esterifid th d cation on a laboratory scale with greater conven- 40 Sen 6 8 ma Ion so 0 w ene ience. Obviously, if one starts with a p'olyhydric had e usedm the step 2 compound having 3 or more hydroxy'ls and adds of the diethyl etherof d1ethyleneglycol then and a dicarboxy acid there is at least some opportuin that event if there had any tenden'qv it for -linkin a formafign of n m wards cross-linking orformation of a gelatinous materials. However, solubility era gelation sheet Compound it y have been desirable to a some can arise in other ways, for instance, possible oxy enat Sol tincipient cross-linking rather than intermediate The data included in subsequent tables, i. 'e., or complete cross-linking-and also the fact that Tables 2 and 3, are self-explanatory and very there are certain limitations as far solubility complete and it is believed no further elaboration goes in any large molecule, to say nothing bf is necessary.

TABLE 2 11 Th .3. 33 53 3 of Acid of h droxyl' d Based Hyd. Polycarboxy Reactant carboxy Ester Oxy. H10 V. of f on Act. Cmpd. Reactant Ompd H. G. a He H. V. (grs. (2

15 2,100 133.5 205 1,355 30.5 15 2,100 33.5 205 1,355 75.5 10 2,100 133.5 205 1,375 104.5 la 2,100 133.5 205 1,355 39.0 15 2,100 133.5 205 1,355 53.7 15 2,100 133.5 205 1,355 57.0 25 3,110 90.0 150 1,355 52.4 25' 3,110 90.0 150 1,355 31.0 25 3,110 90.0 150 1,355 59.0 25 3,110 90.0 150 1,355 59.0 25 3,110 90.0 150, 1,355 47.9 2!! 3, 90. 0 l, 865 52.0 311 5,170 54. 4 99.3 2, 310 33.5 35 5,170 54.4 99.3 2,310 31.5 35 5,170 54.4 99.3 2,310 5 3a 5,170 54.4 99.3 2,310 35.5 35 5,170 54.4 99.3. 2,310 37.0 35 5,170 54.4 99.3 2,310 24.5 p43. 5,320 34.5 31.7 3,430 21.4 45 5,320 34.5 31.7 3,430 32.4 -45 5,320 34.5 31.7 3,430 29.2 40 5,320 34.5 31.7 3, 430 150 013115 Acid 27.5

TABLE 3 Time of Ex. No. Amt. Estenfiof Acid Solvent Solvent cation gigg e m gg Ester (grs.) Temp, 0. (hm) lb Xylene and diethyl 234 145 5% 11.

ether of diethylene gl 01.

The procedure for manufacturing the esters has been illustrated by preceding examples. If for any reason reaction does not take place in a manner that is acceptable, attention should be directed to the following details: (a) Recheck the hydroxyl or acetyl value of the oxypropylated hydroxy compounds of the kind specified and use a stoichiometrically equivalent amount of acid; (b) if the reaction does not proceed with reasonable speed either raise the temperature indicated or else extend the period of time up to 12 or 16 hours if need be; (c) if necessary, use of paratoluene sulfonic acid or some other acid as a catalyst; (11) if the esterification does not produce a clear product a check should be made to see if an inorganic salt such as sodium chloride or sodium sulfate is not precipitating out. Such salt should be eliminated, at least for exploration experimentation, and can be removed by filtering. Everything else being equal, as the size of the molecule increases and the reactive hydroxyl radical represents a smaller fraction of the entire molecule, more difllculty is involved in obtaining complete esterification.

Even under the most carefully controlled conditions of oxypropylation involving comparatively low temperatures and long time of reaction there are formed certain compounds whose composition is still obscure. Such side reaction products can contribute a substantial proportion of the final cogeneric reaction mixture. Various suggestions have been made as to the nature of these compounds, such as being cyclic polymers of propylene oxide, dehydration products with the appearance of a vinyl radical, or isomers of propylene oxide or derivatives thereof, i. e., of an aldehyde, ketone, or allyl alcohol. In some instances an attempt to react the stoichiometric amount of a polycarboxy acid with the oxypropylated derivative results in an excess of the carboxylated reactant for the reason that apparently under conditions of reaction less reactive hydroxyl radicals are present than indicated by the hydroxyl value. Under such circumstances there is simply a residue of the carboxylic reactant which can be removed by filtration or, if desired, the esterification procedure can be repeated using an appropriately reduced ratio of carboxylic reactant.

Even the determination of the hydroxyl value and conventional procedure leaves much to be desired due either to the cogeneric materials previously referred to, or for that matter, the presence of any inorganic salts or propylene oxide. Obviously this oxide should be eliminated.

The solvent employed, if any, can be removed from the finished ester by distillation and particularly vacuum distillation. The final products or liquids are generally amber, dark amber, to reddish-brown and show moderate viscosity, or sometimes increased viscosity in light of what has been said previously in regard to cross-linking, gelation, etc. Unless there is some reason to do otherwise my preference is to handle these esters as 50% solutions in suitable solvents. They can be bleached with bleaching clays, filtering chars, and the like. However, for the purpose of demulsification or the like color is not a factor and decolorization is not justified.

Having thus described my invention, what I claim as new and desire to obtain by Letters Patent is:

1. An acidic fractional ester of (A) a polycarboxy acid with (B) oxypropylated glucose, with the proviso that (a) the oxypropylated glucose be within the molecular weight range of 1500 to 15,000 on an average statistical basis; (b) the glucose represent not more than 12% by weight of the oxypropylated glucose on a statistical basis; and that (c) the preceding provisos be based on complete reaction involving propylene oxide and the glucose; with the proviso that the ratio of (A) to (B) be one mole of the polycarboxy acid for each available hydroxyl radical.

2. The product of claim 1 wherein the polycarboxy acid is a dicarboxy acid.

3. The product of claim 2 wherein the cheatboxy acid has not over 8 carbon atoms.

4. The product of claim 3 wherein the dicarboxy acid is phthalic acid.

5. The product of claim 3 wherein the dicarboxy acid is maleic acid.

6. The product of claim 3 wherein the dicarboxy acid is succinic acid.

7. The product of claim 3 wherein the dlcarboxy acid is cltraconic acid.

115 8. The product of claim 3 wherein the dicarboxy acid is diglycollic acid.

his MELVIN DE GROOTE.

marlq 5 Witnesses to mark:

W. C. ADAMS, I. S. DE Gnoo'rn.

REFERENCES CITED 10 The following references are of record in iihe file of this patent:

UNITED -STATES PATENTS Number Name Date Schorger June .14, 1932 'Brown Sept. 28, 1948 Johnston May 310, 1950 Kesler et a1 July25, 1950 Zief et a1 Feb. v13, 1951 

1. AN ACIDIC FRACTIONAL ESTER OF (A) A POLYCARBOXY ACID WITH (B) OXYPROPYLATED GLUCOSE, WITH THE PROVISO THAT (A) THE OXYPROPYLATED GLUCOSE BE WITHIN THE MOLECULAR WEIGHT RANGE OF 1500 TO 15,000 ON AN AVERAGE STATISTICAL BASIS; (B) THE GLUCOSE REPRESENT NOT MORE THAN 12% BY WEIGHT OF THE OXYPROPYLATED GLUCOSE ON A TATISTICAL BASIS; AND THAT (C) THE PRECEDING PROVISOS BE BASED ON COMPLETE REACTION INVOLVING PROPYLENE OXIDE AND THE GLUCOSE; WITH THE PROVISO THAT THE RATIO OF (A) TO (B) BE ONE MOLE OF THE POLYCARBOXY ACID FOR EACH AVAILABLE HYDROXYL RADICAL. 